Who transmits Lyme disease besides ticks? - briefly
No other vector is known to transmit Borrelia burgdorferi to humans; transmission is limited to infected Ixodes ticks.
Who transmits Lyme disease besides ticks? - in detail
The bacterium Borrelia burgdorferi is primarily spread by Ixodes ticks, but other routes have been documented or investigated.
Human infection can occur through contaminated blood products. Cases of Lyme disease transmission via transfusion have been reported when donors were asymptomatic carriers of the spirochete. Screening of blood donors for Borrelia is not routine, so the risk, although low, persists.
Organ and tissue transplantation represent another possible pathway. Transplanted organs from donors with undiagnosed Lyme disease have transmitted the infection to recipients, leading to systemic symptoms shortly after surgery.
Vertical transmission from mother to fetus has been observed in animal models and a limited number of human cases. Congenital infection may result in joint and neurological manifestations in newborns.
Laboratory exposure is a recognized occupational hazard. Researchers handling cultures of Borrelia without adequate protective measures have contracted the disease through accidental inoculation or mucous membrane contact.
Potential arthropod vectors other than Ixodes ticks have been examined. Studies on Dermacentor and Amblyomma species suggest they can acquire Borrelia during feeding, but experimental evidence for efficient transmission to humans is lacking. Consequently, these insects are not considered reliable vectors.
Summary of non‑tick transmission routes:
- Blood transfusion from infected donors
- Organ or tissue transplantation from infected donors
- Mother‑to‑child transmission during pregnancy
- Occupational exposure in laboratory settings
- Unconfirmed transmission by other hard‑tick species
Each pathway involves distinct risk factors and preventive measures, emphasizing the need for vigilance beyond the classic tick bite scenario.